The HLK Whitehouse Bryophyte Stereo Image Library provides stereo bryophyte images taken by Harold Whitehouse (together with some by his wife) using a special camera. Details of the camera and stereo-photographic techniques can be found in the article "Stereoscopic Photography of Bryophytes" he wrote in the Bryological Times. During the last 30 years of his life he took thousands of photographs, mainly in the British Isles, but also in Continental Europe, Canada, New Zealand and the Pacific. By the time of his death in 2000 he had photographed approximately 80% of the British bryophyte flora. His collection of slides passed to the BBS and thence to National Museum Wales, in Cardiff. The slides were originally designed to be viewed using a hand-held viewer. Almost all species have a left and right image displayed side by side for fusion into a stereo image by those who are able to cross their eyes at will. There are also anaglyphic images to be viewed with red/green spectacles, with the image for the left eye being red, and for the right eye being green. [Information of the supplier, modified]